Chronic obstructive pulmonary disease (COPD) prevalence, morbidity, and mortality vary across countries and across different groups within countries with a direct relation to the prevalence of tobacco smoking. Other risk factors for COPD include genetic factors, longstanding asthma, outdoor air pollution, second-hand smoke exposure, biomass smoke, indoor air pollution, occupational exposures, and tuberculosis . The prevalence and burden of COPD are projected to increase in the coming decades because of continued exposure to COPD risk factors and the changing age structure of the world's population. As these factors are rapidly increasing in developing countries, COPD will become a major health problem, exerting a huge demand on economic and healthcare resources in developing countries [2]. In Egypt, although COPD is a rising significant health problem, data on its prevalence, morbidity, and mortality are still lacking and have to be estimated .

Sirtuin 1 (SIRT1) is a protein/histone deacetylase dependent NAD. It plays a crucial role in various human diseases such as cardiovascular diseases, cancer, inflammation, aging, neurodegenerative disease, obesity and type 2 diabetes. Seven isoforms of the SIRT1 gene (SIRT1- SIRT7) have been determined in mammals. Expression of the SIRT1 gene is regulated by transcription factors such as CREB, FOXO3, HIC1, NF-KB, p53, PARP-2 and PPAR. SIRT1

Inclusion Criteria:

• All patients admitted to Sohag University Hospital, chest department.

Exclusion Criteria:

• Patients with malignancies, any other chronic disease, Individuals with a history of known chronic cardiorespiratory diseases and those with collagen vascular diseases were excluded.

A total of 100 individuals at high risk for COPD were studied from approval of the ethical committee of the Faculty of Medicine, Sohag University. Informed consent was obtained from all participants. 100 healthy control.

All participants will subject to the following: (1) A questionnaire including age, sex, smoking status, presence of chronic cough, chronic sputum production, chest wheezing, and shortness of breath; grading of dyspnea using a modified medical research council (MMRC) dyspnea scale. (2) General examination, including measurements of body weight, height, and BMI. (3) Local chest examination.